Ink fountain in printing presses

ABSTRACT

An ink fountain having a frame and fountain roller, the frame having a generally vertical wall portion to which the blade is secured in overhanging relation defining a longitudinally extending chamber under the blade. Adjusting mechanism for the blade is mounted in the chamber for engagement with the underside of the blade to control the thickness of ink film. A closure plate is provided on the frame for totally enclosing the chamber to prevent entry of paper dust and ink either in liquid form or in the form of airborne mist, the closure plate having a yieldable sealing connection with the blade in the form of a strip of elastomeric material which is sufficiently elastic so as to yieldingly accommodate adjusting movement of the blade.

Unlted States Patent 1 1 1111 3,922,966

Despot 1 Dec. 2, 1975 [54] INK FOUNTAIN IN PRINTING PRESSES 3,121,9042/1964 Scott 101 157 x 3,123,839 3 1964 R 'd 49 488 X [75] Inventor:Janko Despot, Offenbach, Germany 3333381 811967 at 494488 X [73]AssigneeZ Roland offsetmaschinenfabrik 3,456,583 7/1969 Brodie l0l/365Faber Schleicher AG Germany 3,696,74.) 10/1972 Johne et al. l0l/365 [22]Filed: Mar. 4, 1974 Primary ExaminerEdgar S. Burr [2]] Appl- NO'Z447,752 Assistant Examiner-Paul J. Hirsch Attorney, Agent, orF1rm-Wolfe, Hubbard, Leydlg, Voit & Osann, Ltd. [30] Foreign ApplicationPriority Data Mar, 7, 1973 Germany 7308585[U] [57] ABSTRACT An inkfountain having a frame and fountain roller, [52] US. Cl 101/350;101/367 the frame having a generally vVertical wall portion to [51] Int.Cl. B41F 31/06; B41L 27/08 which the Made is secured in overhangingrelation Fleld of Search 364, 366, fining a longitudinally extendingchamber under the 101/169, 350; 49/488 499 blade, Adjusting mechanismfor the blade is mounted in the chamber for engagement with theunderside of References Clted the blade to control the thickness of inkfilm. A clo- UNITED STATES PATENTS sure plate is provided on the framefor totally enclos- 1,724,075 8/1929 English l0l/365 ing the chamber toPrevent entry of P p dust and 1,862,744 6/1932 Fankboner U 101/3 5 inkeither in liquid form or in the form of airborne 2,178,069 10/1939Crafts 101/157 mist, the closure plate having a yieldable sealing con-2,550,454 4/1951 Crafts et al. 101/157 nection with the blade in theform of a strip of elasto- 2717550 9/1955 l01/169 X meric material whichis sufficiently elastic so as to 217181848 9/1955 Crafts 01/364yieldingly accommodate adjusting movement of the 2,837,024 6/1958 Dougan101/365 blade 2,945,437 7/1960 Hilgoe et al. lOl/364 X 3,040,442 6/1962Overton 101/169 X 1 Claim, 1 Drawing Figure US. Patent Dec. 2, 1975 INKFOUNTAIN IN PRINTING PRESSES The usual type of ink fountain employs afountain blade having a plurality of adjusting screws arranged atclosely spaced intervals along its length for localized adjustment ofthe gap between the tip of the blade and the fountain roller, thereby toadjust the thickness of the film of ink deposited on the fountainroller. The adjustment calls for a high degree of precision andreproducibility, with a portion of the blade closely following" movementof each screw in both directions without any lag or stickiness.

It is the object of the present invention to provide an ink fountainwhich offers the necessary precision of adjustment not only when thefountain is initially installed but which retains the same precisionafter many years of hard usage. It is a more specific object of theinvention to provide an ink fountain which is accurately and sensitivelyadjustable over long periods of time in spite of the contaminants in theform of paper dust in combination with dried or gummy ink which degradesthe adjustability of conventional designs of fountains. Indeed, it is anobject to provide a fountain adjusting mechanism which is capable ofoperating over long periods of time unaffected even by the airborne inkmist usually present in an operating press room.

Other objects and advantages of the invention will become apparent uponreading the attached detailed description and upon reference to thedrawing which shows a vertical cross section taken through an inkfountain of my improved design.

The general type of ink fountain to which the present invention isapplicable includes a longitudinally extending frame having end memberswhich journal the fountain roller together with means for driving thefountain roller at a low rate of speed. Since journaling in end membersand driving are conventional and do not form a part of the presentinvention, such structure has, for simplicity, been omitted from thedrawing.

The frame of the ink fountain includes a vertically extending wallportion 11 having, along its upper edge, a flat supporting surface 12.At the foot of the wall 11 is a generally horizontally extending baseportion 13.

Mounted upon the supporting surface 12 is a fountain blade 15 which isheld in place by screws or the like 16 and which has a longitudinallyextending tip portion 17. The tip of the blade is spaced closelyadjacent the surface of the fountain roller 18. Pocketed between theblade and the roller is a body of ink I, with the result that, as theroller turns, a film of ink 19 is formed on its surface. As will beunderstood by one skilled in the art, such film is transferred to aseries of ink rollers and drums (not shown), a portion of which areusually vibrated endwise, so that a thin and consistent film of inkreaches the form roller for transfer to the printing plate.

In carrying out the invention the base portion of the frame is laterallyprojecting and the blade is mounted overhangingly so that the blade andbase portion define between them a longitudinally extending chamber. Themeans for adjusting the blade spacing is mounted within this chamber,and the chamber is enclosed by a longitudinal closure plate, the loweredge of which is sealed to the frame and the upper edge of which issealed by a strip of resilient material to the underside of the blade sothat the chamber is tightly shielded against the entry of foreignmaterial, either liquid or airborne, in all positions of adjustment ofthe blade.

Turning attention to the adjusting means, an adjusting screw 20 isprovided which penetrates the wall portion 11 of the frame with a snugfit, the tip 21 of the screw being located within the chamber withfreedom for endwise movement. Coupled to the tip of the screw is anadjusting member in the form ofa crank 22 which is rockably swingableabout a horizontal pin 23 supported in a bracket 24, the lower end 25 ofthe pin being captive in the tip of the screw. The upper portion of thecrank 22 is formed into a cam surface 26 which is engaged by a camfollower member 27 which is secured to the underside of the tip portionof the blade. It will be apparent that the profile of the cam 26 mayvary over wide limits, the only requirement being that the cam surfacebe eccentric with respect to the pin axis to a degree and directionsufficient to provide the desired amount of throw of the blade withinthe range of movement of the adjusting screw.

. In accordance with the invention the chamber defined by theoverhanging blade and projecting base, and which is indicated by numeral29, is enclosed by a closure plate 30 having an upper edge 31 and loweredge 32, it being understood that the closure plate is sufficiently longso as to extend into sealed engagement with the non-illustrated endmembers of the fountain frame. For securing and sealing the lower edgeof the closure plate to the base 13, a longitudinal mounting bar 35 isprovided which is preferably coextensive with the closure plate andwhich abuts against mounting pads 36, to which the bar and closure plateare secured by appropriate screws 37. Thus by means of the bar 35 thelower edge of the plate 30 is sealed tightly and continuously to thebase 13.

his one of the features of the invention that a resilient sealing stripis interposed between the upper edge of the closure plate and the tip ofthe blade so as to maintain an impervious seal between the closure plateand the blade throughout the range of movement of the blade. Morespecifically, there is interposed between the blade a resilient strip ofelastomeric material, such as rubber, which may be vulcanized to theclosure plate and which has sufficient resiliency to yieldinglyaccommodate movement of the blade, without breaking the seal, eventhough the closure plate is stationarily anchored along its lower edge.In the present embodiment the strip of elastomeric material, indicatedat 40, is mounted in a relatively wide longitudinal groove 41 formed inthe underside of the cam follower member 27 which, in turn, is securelyfixed to the underside of the blade. The upper edge of the closure plateextends centrally into the inverted U-shaped cross section of the stripand is thus tightly sealed on both sides. The strip is of relativelythick section between the mounting surfaces and is of flexible,relatively soft material. Moreover, the amount of blade movement issufficiently limited and the mechanical advantage of the adjustingmechanism is sufficiently great so that the restoring force of therubber strip is readily overcome, either in tension or compression, anddoes not affect the free adjusting movement of the blade. Indeed, thereactive stress of the strip may simply, as a minor factor, be added to,or subtracted from, the reactive force of the blade, depending uponwhether the strip is, at a given point of adjustment, in tension orcompression.

By use of the invention the longitudinally extending chamber 29, whichmay be broken up into sections by mounting pads 26, or which may becontinuous is, nevertheless, tightly and continuously sealed against theentry of contaminants, primarily ink and paper dust and particularly acombination of the two. The integrity of the seal is such that evenairborne ink mist is prevented from entering and building up on thesurfaces so that there is no possibility of the mechanism being degradedin its accuracy and responsiveness as a result of passage of time.Specifically, there is no possibility that dried ink may accumulate andinterpose itself between the cam surface 26 and follower 27; on thecontrary, accurate and consistent metal-to-metal" contact is maintainedin this critical region for the life of the fountain. Moreover, bykeeping the thread of the screw 20 completely isolated against depositsof gummy ink, the screw remains free turning which is particularlydesirable where the screw is rotated by a remotely controlled servo typedrive motor of limited torque capability.

While the invention has been described in connection with a single screwand blade adjusting mechanism, one skilled in the art will appreciatethat such mechanisms are provided in multiple, as an evenly spacedseries, along the length of the blade for zonal or column-by-column,control of ink flow. Accordingly, the blade may be of slit constructionwith sections, for example corresponding to column positions, arrangedso closely side by side as to preclude any ink leakage. As a practicalmatter, the blade 15 may, as shown, be of composite construction inwhich the heavy base portion of the blade is slit on a zonal basis whilethe thin top portion is in tact from end to end. It will be understoodthat in the case of a slit blade the cam follower elements 27 will havean axial length equal to the width of the controlled section of blade,but the resilient strip 41 may, nonetheless, extend continuously overthe length of the fountain with unbroken sealing integrity.

While the invention may take a number of forms within the scope of theappended claims, it is preferred to have the strip 40 of elastomericmaterial, i.e. rubber, continuously bonded to the upper edge of theclosure plate and continuously bonded to the underside of the blade inthe-region of its tip so that adjusting movement of the blade isaccommodated by elastic deformation. This type ofjoint is preferred overa slidable joint since deformation of the rubber is immune tocollections of gummy or dried ink which may build up on the exposed sidewhereas a joint providing relative sliding movement may be subject tostickiness. Nevertheless, the invention in certain of its aspects is notlimited to actual bonding or vulcanization provided that an elastomericstrip is used. For example, the closure plate 30, if unbonded to thestrip 40, and hence slidable with respect to it, should develop anystickiness, relative movement would, thereafter, be accommodated bydeformation of the strip so that the effect would be the same regardlessof whether there is intentional bonding.

It will be apparent to one skilled in the art that the advantages of theinvention may be achieved economically both in the case of new andexisting designs of ink fountains.

I claim:

1. ln an ink fountain, the combination comprising a frame, a fountainroller mounted in the frame and extending parallel to it, theframeincluding a vertically extending wall portion providing an upwardlyfacing supporting surface as well as a base portion, a fountain bladesecured to the supporting surface and having a projecting portionterminating in a tip extending into operative engagement with the undersurface of the roller to define an ink film thereon said blade having onits bottom side a cam follower portion spaced inwardly of said tip, thebase portion projecting laterally from the wall in the same direction asthe blade, the projecting portion of the blade and base portion of theframe vertically opposed thereto being of approximately equal dimensionand together defining a longitudinal chamber under the blade, a body ofink above the blade, means for rotating the roller so that its surfacerotates downwardly through the body of ink, adjusting mechanism in thechamber engaging the underside of the blade and including a series ofadjusting screws which penetrate the wall portion and which are sealedwith respect to it, the screws having individual cams engaging the bladealong said cam follower portion so that as the screws are operated thetip of the blade undergoes localized adjusting movement toward and awayfrom the surface of the fountain roller, a closure plate which extendsgenerally vertically so as to make an obtuse angle with the blade aswell as extending longitudinally of the frame to enclose the chamber,said closure plate having an upper edge extending to within a shortdistance of the underside of the blade adjacent said tip and having alower edge which is stationarily secured to the laterally extending baseportion of the frame for making a leakage tight joint with the latter,and a resilient strip extending continuously along the upper edge of theclosure plate to seal the joint between the closure plate and theunderside of the fountain blade so that the chamber is substantiallysealed against paper dust and ink either in liquid form or in the formof airborne ink mist, the strip being formed of elastomeric materialcontinuously joined to the upper edge of the closure plate andcontinuously joined to the underside of the blade at the tip thereof soas to enclose within the chamber, the screws, cams, and cam followerregion, the strip being sufficiently resilient so that localizedadjusting movements of the blade are accommodated by elastic deformationof the resilient strip while preserving the integrity of the seal.

1. In an ink fountain, the combination comprising a frame, a fountainroller mounted in the frame and extending parallel to it, the frameincluding a vertically extending wall portion providing an upwardlyfacing supporting surface as well as a base portion, a fountain bladesecured to the supporting surface and having a projecting portionterminating in a tip extending into operative engagement with the undersurface of the roller to define an ink film thereon said blade having onits bottom side a cam follower portion spaced inwardly of said tip, thebase portion projecting laterally from the wall in the same direction asthe blade, the projecting portion of the blade and base portion of theframe vertically opposed thereto being of approximately equal dimensionand together defining a longitudinal chamber under the blade, a body ofink above the blade, means for rotating the roller so that its surfacerotates downwardly through the body of ink, adjusting mechanism in thechamber engaging the underside of the blade and including a series ofadjusting screws which penetrate the wall portion and which are sealedwith respect to it, the screws having individual cams engaging the bladealong said cam follower portion so that as the screws are operated thetip of the blade undergoes localized adjusting movement toward and awayfrom the surface of the fountain roller, a closure plate which extendsgenerally vertically so as to make an obtuse angle with the blade aswell as extending longitudinally of the frame to enclose the chamber,said closure plate having an upper edge extending to within a shortdistance of the underside of the blade adjacent said tip and having alower edge which is stationarily secured to the laterally extending baseportion of the frame for making a leakage tight joint with the latter,and a resilient strip extending continuously along the upper edge of theclosure plate to seal the joint between the closure plate and theunderside of the fountain blade so that the chamber is substantiallysealed against paper dust and ink either in liquid form or in the formof airborne ink mist, the strip being formed of elastomeric materialcontinuously joined to the upper edge of the closure plate andcontinuously joined to the underside of the blade at the tip thereof soas to enclose within the chamber, the screws, cams, and cam followerregion, the strip being sufficiently resilient so that localizedadjusting movements of the blade are accommodated by elastic deformationof the resilient strip while preserving the integrity of the seal.